package cn.hwl.springframework.beans.factory.xml;

import cn.hutool.core.util.StrUtil;
import cn.hutool.core.util.XmlUtil;
import cn.hwl.springframework.beans.BeansException;
import cn.hwl.springframework.beans.PropertyValue;
import cn.hwl.springframework.beans.factory.config.BeanDefinition;
import cn.hwl.springframework.beans.factory.config.BeanReference;
import cn.hwl.springframework.beans.factory.support.AbstractBeanDefinitionReader;
import cn.hwl.springframework.beans.factory.support.BeanDefinitionRegistry;
import cn.hwl.springframework.core.io.Resource;
import cn.hwl.springframework.core.io.ResourceLoader;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import java.io.IOException;
import java.io.InputStream;

/**
 * @author :  HuangWL
 * @date :    2022/4/27 13:43
 * doLoadBeanDefinitions 实际加载方法
 */
public class XmlBeanDefinitionReader extends AbstractBeanDefinitionReader {

    public XmlBeanDefinitionReader(BeanDefinitionRegistry registry) {
        super(registry);
    }

    public XmlBeanDefinitionReader(BeanDefinitionRegistry registry, ResourceLoader resourceLoader) {
        super(registry, resourceLoader);
    }

    @Override
    public void loadBeanDefinitions(Resource resource) throws BeansException {

        try {
            try (InputStream inputStream = resource.getInputStream()) {
                doLoadBeanDefinitions(inputStream);
            }
        } catch (IOException|ClassNotFoundException e) {
            throw new BeansException("IOException parsing XML document from " + resource, e);
        }
    }

    @Override
    public void loadBeanDefinitions(Resource... resources) throws BeansException {
        for (Resource resource : resources) {
            loadBeanDefinitions(resource);
        }
    }

    @Override
    public void loadBeanDefinitions(String location) throws BeansException {
        ResourceLoader resourceLoader = getResourceLoader();
        Resource resource = resourceLoader.getResource(location);
        loadBeanDefinitions(resource);
    }

    @Override
    public void loadBeanDefinitions(String... locations) throws BeansException {
        for (String location : locations) {
            loadBeanDefinitions(location);
        }
    }

    public void doLoadBeanDefinitions(InputStream inputStream) throws ClassNotFoundException {
        Document doc = XmlUtil.readXML(inputStream);
        Element root = doc.getDocumentElement();
        NodeList childNodes = root.getChildNodes();

        for (int i =0; i < childNodes.getLength();i++){
            //判断元素 子节点类型不与父节点类型一样则抛弃
            if (!(childNodes.item(i) instanceof Element)){
                continue;
            }
            //判断对象 子节点名字不为  bean 则抛弃
            if (!"bean".equals(childNodes.item(i).getNodeName())){
                continue;
            }
            //解析标签
            Element bean = (Element)childNodes.item(i);
            String id = bean.getAttribute("id");
            String name = bean.getAttribute("name");
            String className = bean.getAttribute("class");
            //获取Class，方便获取其中的值
            Class<?> clazz = Class.forName(className);
            //优先级  id >  name
            String beanName = StrUtil.isNotEmpty(id)? id:name;
            if (StrUtil.isEmpty(beanName)){
                beanName = StrUtil.lowerFirst(clazz.getSimpleName());
            }

            BeanDefinition beanDefinition = new BeanDefinition(clazz);
            //读取属性并填充
            for (int j = 0; j < bean.getChildNodes().getLength(); j++) {
                if (!(bean.getChildNodes().item(j) instanceof Element)) {
                    continue;
                }
                if (!"property".equals(bean.getChildNodes().item(j).getNodeName())) {
                    continue;
                }
                // 解析标签：property
                Element property = (Element) bean.getChildNodes().item(j);
                String attrName = property.getAttribute("name");
                String attrValue = property.getAttribute("value");
                String attrRef = property.getAttribute("ref");
                // 获取属性值：引入对象、值对象
                Object value = StrUtil.isNotEmpty(attrRef) ? new BeanReference(attrRef) : attrValue;
                // 创建属性信息
                PropertyValue propertyValue = new PropertyValue(attrName, value);
                beanDefinition.getPropertyValues().addPropertyValue(propertyValue);
            }
            //判断bean 名是否已被注册
            if (getRegistry().containsBeanDefinition(beanName)) {
                throw new BeansException("Duplicate beanName[" + beanName + "] is not allowed");
            }
            //注册 BeanDefinition
            getRegistry().registerBeanDefinition(beanName, beanDefinition);
        }
    }
}
